Internal stability of geosynthetic reinforced soil walls : Calculations procedures for practical design

Reinforced soil constructions have a long history, and various types of the soil reinforcement havebeen in use since the medieval period. Geosynthetic reinforced soil walls (GRS-walls) while beingcommon throughout the world, in not included in the current Eurocode for geotechnical design, SSEN1997-1. The Swedish transportation authority design guidelines (TK Geo 13 and TR Geo 13)provides requirements regarding the utilization of the bearing capacity of the reinforcedgeosynthetic layer and suggestions for the calculation model, but the design is free to choose asuitable design model. Since geosynthetics are very flexible, the load distribution between thegeosynthetic layers in the GRS-wall will be dependent on the stress-strain response of the soil andthe geosynthetic layers. This thesis evaluates the importance of the design model on the ultimatelimit state (ULS) as well as the serviceability limit state (SLS) on a typical GRS wall. The resultsshows that a full numerical model including the stress-strain development gives less utilization ofthe geosynthetic layers at a comparable surcharge load compared to a limit equilibrium model(LEM) suggested by TR Geo. Furthermore, the redistribution of the load between the geosyntheticlayers result in a significantly larger maximum load before a collapse state compared to the LEMcalculation. In such structures the serviceability conditions will control the design. Theconsequences for practical design and the limitation to various design models are elaborated andrecommendations are given